Design And Implementation Of Control System For Four-rotor UAV

The four-rotor UAV has been widely used in military,civil,scientific research and education fields because of its advantages of convenient carrying,simple structure,low price and strong mobility.The influence of natural wind on the four-rotor UAV can not be ignored,which is one of the main reasons for limiting the use of the four-rotor UAV.In order to solve the problem of weak anti-wind ability of four-rotor UAV and improve the adaptability of four-rotor UAV to harsh environment,this paper presents a controller design which can improve its anti-wind performance combined with the subject of Anshan Research Institute of Harbin Institute of Technology.Firstly,according to the characteristics of the translational and angular motion of the four-rotor UAV,the dynamic equations of the four-rotor are established in combination with coordinate transformation.The related wind speed model is established to analyze the flight state of the four-rotor in the presence of wind disturbance and to discuss the effect of natural wind on the four-rotor UAVs.According to the dynamic equations of the four-rotor,the attitude sliding mode controller based on the proportional switching method and the attitude sliding mode controller based on the exponential approach law are designed,respectively.By comparing the two methods,the one with better control effect is used as the final controller.Then the hardware system of four-rotor UAV is designed,including the selection of UAV power system and the hardware design of flight control system.An independent power supply system is designed to meet the demand of different devices.The selection of attitude and position sensor and the circuit design of flight control board are carried out.Finally,the software design of flight control system is carried out by using top-down hierarchical design idea.For multi-task execution with different call frequency,the design of task scheduling is put forward,which completes the real-time scheduling of multi-task.Through the outdoor flight experiment of the four-rotor UAV,it is proved that the controller designed in this paper can make the four-rotor aircraft have better anti-wind disturbance effect.